Solve for $x$ : $9\sqrt{x} + 6 = 2\sqrt{x} + 4$
Answer: Subtract $2\sqrt{x}$ from both sides: $(9\sqrt{x} + 6) - 2\sqrt{x} = (2\sqrt{x} + 4) - 2\sqrt{x}$ $7\sqrt{x} + 6 = 4$ Subtract $6$ from both sides: $(7\sqrt{x} + 6) - 6 = 4 - 6$ $7\sqrt{x} = -2$ Divide both sides by $7$ $\frac{7\sqrt{x}}{7} = \frac{-2}{7}$ Simplify. $\sqrt{x} = -\dfrac{2}{7}$ The principal root of a number cannot be negative. So, there is no solution.